Tìm x:
A)2/3.x-4/7=1/8
B)2/7-8/9.x=2/3
C)4/7+5/9:x=1/5
Đ)2/5-2/5.x=2/4
E)(2,8.x-32:2/3=90
F)(4,5-3.x).11/4=11/4
Đ)
Tìm x: A)2/3.x-4/7=1/8 B)2/7-8/9.x=2/3 C)4/7+5/9:x=1/5 Đ)2/5-2/5.x=2/4 E)(2,8.x-32:2/3=90 F)(4,5-3.x).11/4=11/4 Đ)
By Elliana
Đáp án:
a) 2/3. x – 4/7 = 1/8
2/3. x = 1/8 + 4/7
2/3. x = 39/56
x = 39/56 : 2/3
x = 117/112
b) 2/7 – 8/9. x = 2/3
8/9. x = 2/7 – 2/3
8/9. x = -8/21
x = -8/21 : 8/9
x = -3/7
c) 4/7 + 5/9: x = 1/5
5/9: x = 1/5 – 4/7
5/9: x = -13/35
x = 5/9 : ( -13/35 )
x = -175/117
d) 2/5 – 2/5. x = 2/4
2/5. x = 2/5 – 2/4
2/5. x = -1/10
x = -1/4
e) (2,8. x – 32) : 2/3 = 90
2,8. x – 32 = 90 . 2/3
2,8. x – 32 = 60
2,8. x = 60 + 32
2,8. x = 92
x = 230/7
f) (4,5 – 3. x). 11/4 = 11/4
4,5 – 3. x = 11/4 : 11/4
4,5 – 3. x = 1
3. x = 4,5 – 1
3. x = 3,5
x = 7/6